• Journal of Korean Neurosurgical Society
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• v.61 no.4
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• pp.458-466
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• 2018

Objective : To compare peri-operative any symptomatic stroke after carotid angioplasty and stenting (CAS), based on the application or absence of a cerebral protection device. Methods : A systematic literature review using PubMed, Embase, and the Cochrane Central was done across an online data base from January 1995 to October 2016. Procedures which were performed due to carotid dissection or aneurysm, procedures using covered stents or conducted in an emergency, were excluded. The primary endpoint was perioperative any symptomatic stroke within 30 days after the procedure. A fixed effect model was used in cases of heterogeneity less than 50%. Results : In the 25 articles included in this study, the number of stroke events was 326 (2.0%) in protected CAS and 142 (3.4%) in unprotected CAS. The use of cerebral protection device significantly decreased stroke after CAS (odds ratio [OR] 0.633, 95% confidence interval [CI] 0.479-0.837, p=0.001). In the publication bias analysis, Egger's regression test disclosed that the intercept was -0.317 (95% CI -1.015-0.382, p=0.358). Regarding symptomatic patients (four studies, 539 CAS procedures), the number of stroke was six (1.7%) in protected CAS and 11 (5.7%) in unprotected CAS. The protective effect against stroke events by cerebral protection device did not have a statistical significance (OR 0.455, 95% CI 0.151-1.366, p=0.160). Conclusion : The use of protection device significantly decreased stroke after CAS. However, its efficacy was not demonstrated in symptomatic patients. Routine use of protection device during CAS should be critically assessed before mandatory use.

• Journal of Dental Anesthesia and Pain Medicine
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• v.15 no.1
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• pp.17-23
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• 2015

Background: Dental injury as a result of oroendotracheal intubation during general anesthesia is very common. We report our experiences of using mouthguard to prevent dental injury during intubation based on our protocol. Methods: This retrospective study enrolled patients referred for preanesthetic evaluation, those patients with a history of any of the dental treatments to their anterior teeth listed on our fabrication protocol from January 1, 2009 to June 30, 2010. Results: No cases of dental trauma during oroendotracheal intubation were reported among the 202 patients who used a protective device. 66% of the patients had risk factors for hard tissue damage aged 10-40 years. At the ages of 40-70 years, the incidence of risk group for periodontal damage was higher. Conclusions: Preanesthetic consultation was effective for preventing dental injury, so preanesthetic questionnaire and proper dental consultation would be helpful.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.2
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• pp.60-67
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• 2006

This paper presents the protection effect of surge protective devices(SPDs) according to the conditions of installations. To propose the effective protection measures of information and communication equipments against lightning surges, actual-sized experiments in relation to the protection effects on the positions of installations of SPDs, the length of branch circuit, the wiring methods, and the materials of conduit, were conducted. The effective method of protecting information and communication equipments from lightning surges is to install SPDs in the vicinity of input terminals of each electronic equipments to be protected. The wiring method of connecting an SPD minimizing the length of leads is desirable when point-to-point wiring is to be used.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.4
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• pp.527-532
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• 2012

Recently, in power system, even though the needs of protective IED(Intelligent Electronic Device) is highly increased, there are some problems in the field when use the IED. When the IED is in the fluctuated overload condition, because of the existing algorithm calculate the trip time only with the measured current of just previous measuring stage, the calculated trip time is not a proper value for the overload protection at this kind of condition, and when the load current fluctuate between overload and normal condition, because of the instantaneous reset characteristic of existing algorithm the IED dose not trip. And the non linear loads using power electronic elements seem to be increased. These non linear loads require a counterplan about various harmonics incoming to electric power systems. So we will give solutions about these problems.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.7
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• pp.70-76
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• 2012

In general, the unidirectional power flow is normal in distribution feeders before activation of distributed power source such as PV. However, the interactive power flow is likely to occur in case of the power system under distributed generation. This interactive power flow can cause an unexpected effect on convectional protection coordination systems designed based only on the unidirectional power flow system. When the power line system encounters a problem, the interactive power flow can be a contributed current source and this makes the fault current bigger or smaller compared to the unidirectional case. The effect of interactive power flow is varied depending on the location of the point to ground fault, relative location of the PV, and connection method. Therefore it is important to analyse characteristics of fault current and interactive flow for various transformer connection and location of the PV. This paper proposes a method of improved protection coordination which can be adopted in the protective device for customers in distribution feeders interconnected with the PV. The proposed method is simulated and analysed using PSCAD/EMTDC under various conditions.

• Proceedings of the KIEE Conference
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• 2001.11b
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• pp.340-343
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• 2001

In an electrical network, electrical power are transmitted by a various of protection, isolation and control electric circuit devices. This thesis deals with the protection function between circuit-breakers. The protective coordination concerns the behaviour of two devices placed in series in an electrical network, with a short-circuit downstream circuit-breaker. It has two basic principles: First, discrimination which is an increasing requirement of low voltage electrical distribution systems. Second, which is less well known: cascading, which consists of installing a device, whose breaking capacity is less than the three-phase short-circuit current at its terminals and helped by main circuit-breaker. The important advantage of cascading is to be able to install at a branch circuit-breaker of a lesser performance without endangering the safety of the installation for more economical usage. To determine and guarantee co-ordination between two circuit breakers, it is necessary to carry out a theoretical approach, first, and then confirm the results by means of standard tests. This is illustrated in appendix A of IEC 947-2.

• Korean Journal of Occupational Health Nursing
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• v.8 no.2
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• pp.169-175
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• 1999

The study was purposed to know the status of health management in small-scale-industries which have less than 50 employees. A total of 330 small-scale-industries were surveyed by nurses and industrial-hygienists who were affiliated with industrial health care agency from January, 1993 to December, 1994. The contents of survey include status of work environment, occupational accident and its disease availability, protective evice, health education and settlements. The results were as follows: 1. The number of industrial accidents(death, injury arid occup. disease) in 1994 was 83 which was reduced from that of the 1993 which was 126. 2. As a result of the measurement of work environment the excessive ratio of permitted criteria was reduced to 20.6% in 1994 from 264% in 1993, and the improvement ratio of work environment was increased to 39.5% in 1994 from 29.7% in 1993. 3. The contents of health education at work place were as follows: general disease(25.4%), work environment(20.2%), protective device(16.7%), disease prevension(14.2%), occupational disease(85%), and health promotion(8.3%). 4. In terms of industrial safty and prevention of occupational disease, only 10.6% was satisfactory or excellent, and the 89.4% was poor, inadequate or required reexamination.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.5
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• pp.95-103
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• 2013

Protection of the electrical and electronic equipment against surges in low voltage AC power distribution systems is based on wide applications of surge protective devices(SPDs). Cascade application of SPDs located at the service entrance of a building and near sensitive equipment is intended to ensure the optimal voltage protection level and energy sharing among cascade SPDs. In this paper, when surges impinge at the service entrance of the building of interest, the protection characteristics of two-stage cascade SPD systems were investigated. The influence of the distance between the upstream and downstream SPDs on the voltage protection level and energy sharing of the two-stage cascade SPD systems were analyzed experimentally. It was found that the energy sharing of two-stage cascade SPD systems strongly depends on the distance between the two SPDs and the component of SPD. As the distance between the two SPDs increases, the energy absorbed by the upstream SPD increases while the energy absorbed by the downstream SPD decreases. Consequently, it is desirable to select the upstream and downstream SPDs having the proper energy capability with due consideration of the distance between the two SPDs.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.1
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• pp.20-25
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• 2011

This paper analyzed the application of Superconducting Fault Current Limiter (SFCL) on 22.9 [kV] bus tie in a power distribution system. Commonly, the parallel operations of power main transformers offer a lot of merits. However, when a fault occurs in the parallel operation of power main transformer, the fault currents might exceed the interruption capacity of existing protective devices. To resolve this problem, thus, the SFCL has been studied as the fascinating device. In case that, Particularly, the SFCL could be installed to parallel operation of various power main transformers in power distribution system of the Korea Electric Power Corporation (KEPCO) on 22.9 [kV] bus tie, the effect of the resistance of SFCL could reduce the increased fault currents and meet the interruption capacity of existing protective devices by them. Therefore, we analyzed the effect of application and proposed the proper impedance of the R-type SFCL on 22.9 [kV] bus tie in a power distribution system using PSCAD/EMTDC.

• Journal of Korean Biological Nursing Science
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• v.21 no.4
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• pp.318-325
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• 2019

Purpose: The purpose of this study was to identify the effects of a finger guard developed to prevent sharp injuries in nursing students. Methods: This study was an equivalent control group posttest design. Seventy nursing students were randomly allocated to either the experimental group (n= 35) or the control group (n= 35). The finger guard was used whileopening the glass ampoule in the experimental group. The outcome variables such as sharp injuries, anxiety and user satisfaction were measured. Results: Sharp injuries were 0 in the experimental group and 2 in the control group (p= .160). Anxiety in the experimental group was significantly lower than the control group (p< .001). User satisfaction was 4.33 score in the range from 1 to 5, the highest item was the weight (4.63), followed by effectiveness (4.51). Conclusion: Using a protective device while opening the glass ampoule was observed to be effective in reducing anxiety among the nursing students, and exhibited protection of skin.